特高压柔性直流桥臂电抗器故障特性与保护策略仿真研究

Simulation Research on Fault Characteristics and Protection Strategy of UHV Flexible DC Bridge Arm Reactor

基于乌东德电站送电广东广西特高压多端直流示范工程柳州换流站实际运维中遇到的桥臂电抗器异常情况,首先分析换流器桥臂中的二倍频环流与桥臂电抗器的关系,然后通过在PSCAD软件中建立仿真模型,仿真分析桥臂电抗器发生短路故障前后桥臂电流中二次谐波分量的变化情况,提出优化相关保护动作逻辑的解决方案,以辅助运行人员监视桥臂电抗器运行工况,避免桥臂电抗器短路时无异常告警或动作跳闸,导致故障进一步扩大。

Abnormal condition of bridge arm reactor occurred in Liuzhou converter station of Guangdong Guangxi UHV multi terminal DC demonstration project in Wudongde power station.Firstly,the relationship between the second harmonic circulating current in the bridge arm and the bridge arm reactor is analyzed.Then the simulation model is established in PSCAD software to simulate and analyze the change of the second harmonic component in the bridge arm current before and after the bridge arm reactor short-circuit fault.A solution to optimize the action logic of the relevant protection is proposed so as to assist the operators to monitor the operation condition of the bridge arm reactor,and avoid no abnormal alarm or action trip when the bridge arm reactor is short circuited,which leads to further expansion of the fault.